Technical Field
The present invention relates to selecting a relay device that relays content data, from among a plurality of relay devices.
Description of the Related Art
An example of a transmission system that performs transmission/reception of content data between a plurality of transmission terminals via a relay device includes a videoconference system that holds a videoconference via a communication network such as the Internet. There is an increasing need for such videoconference systems due to reduction in business trip costs and time in recent years. In such a videoconference system, a plurality of videoconference terminals, which are examples of transmission terminals, is used. A videoconference can be realized by transmission/reception of image data and sound data between these videoconference terminals.
In addition, the recent improvement of broadband circumstances contributes to transmission/reception of high-quality image data and high-quality sound data. Accordingly, it becomes easier to detect the circumstances of a communication partner in a videoconference, and hence conversation-based communication becomes more productive.
However, when many videoconferences are being held via a communication network or when image data and sound data are being received using a narrowband path on a communication network, reception of image data and sound data is delayed. It is said that a delay of 0.5 seconds or greater in reception of image data and sound data makes a user of a videoconference system feel stressed during conversation. Therefore, although the broadband environment has become more elaborate in recent years, there are circumstances where no videoconference satisfactory to users can be held.
In recent videoconference systems, a relay device that relays image data and sound data between videoconference terminals is provided for each local area network (LAN) in a communication network. With the use of such relay devices, communication processing in a videoconference is distributed, thereby reducing the load on each relay device, and the amount of data transmission, such as image data and sound data to be relayed, can be distributed.
In the case of selecting and using one relay device from among a plurality of relay devices, a relay device connected to a LAN to which a videoconference terminal holding a videoconference is connected as well is used. That is, by selecting a relay device with an Internet protocol (IP) address that is similar to the IP address of a videoconference terminal, high-quality image data and the like are transmitted/received via the selected relay device.